Zhang Jinghui, Yu Zhou, You Guofeng
Department of Pharmaceutics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
Acta Pharm Sin B. 2020 Jan;10(1):186-194. doi: 10.1016/j.apsb.2019.05.005. Epub 2019 Jun 5.
Organic anion transporter 3 (OAT3) plays a vital role in removing a broad variety of anionic drugs from kidney, thus avoiding their possible toxicity in the body. In the current study, we investigated the role of insulin-like growth factor 1 (IGF-1) in the regulation of OAT3. We showed that IGF-1 induced a dose- and time-dependent increase in OAT3 transport activity, which correlated well with an increase in OAT3 expression. The IGF-1-induced increase in OAT3 expression was blocked by protein kinase A (PKA) inhibitor H89. Moreover, IGF-1 induced an increase in OAT3 phosphorylation, which was also blocked by H89. These data suggest that the IGF-1 modulation of OAT3 occurred through PKA signaling pathway. To further confirm the involvement of PKA, we treated OAT3-expressing cells with PKA activator Bt2-cAMP, followed by examining OAT activity and phosphorylation. We showed that OAT3 activity and phosphorylation were much enhanced in Bt2-cAMP-treated cells as compared to that in control cells. Finally, linsitinib, an anticancer drug that blocks the IGF-1 receptor, abrogated IGF-1-stimulated OAT3 transport activity. In conclusion, our study demonstrated that IGF-1 regulates OAT3 expression and transport activity through PKA signaling pathway, possibly by phosphorylating the transporter.
有机阴离子转运体3（OAT3）在从肾脏清除多种阴离子药物中起着至关重要的作用，从而避免它们在体内可能产生的毒性。在本研究中，我们调查了胰岛素样生长因子1（IGF-1）在OAT3调节中的作用。我们发现IGF-1以剂量和时间依赖性方式诱导OAT3转运活性增加，这与OAT3表达增加密切相关。IGF-1诱导的OAT3表达增加被蛋白激酶A（PKA）抑制剂H89阻断。此外，IGF-1诱导OAT3磷酸化增加，这也被H89阻断。这些数据表明IGF-1对OAT3的调节是通过PKA信号通路发生的。为了进一步证实PKA的参与，我们用PKA激活剂Bt2-cAMP处理表达OAT3的细胞，然后检测OAT活性和磷酸化。我们发现与对照细胞相比，Bt2-cAMP处理的细胞中OAT3活性和磷酸化显著增强。最后，一种阻断IGF-1受体的抗癌药物林西替尼消除了IGF-1刺激的OAT3转运活性。总之，我们的研究表明IGF-1通过PKA信号通路调节OAT3表达和转运活性，可能是通过使转运体磷酸化来实现的。
